The present invention relates to the tip of an ultrasonic endoscope hating a radially scanning annular ultrasonic oscillator array provided at the distal end of the insertion portion.
Ultrasonic endoscopes are capable of optical examination of the surface of a membrane in a body cavity while producing an ultrasonic cross-sectional image of the tissue under the membrane They are tools useful not only for inspection but also for surgical treatment.
The ultrasonic endoscopes that serve these purposes are provided with not only a system for optical examination and a system for ultrasonic scanning but also a system for projecting treatment tools such as an injecting syringe.
Surgical treatment with endoscopes is called an endoscopic treatment and its kind and the scope of its application vary considerably depending upon whether two treatment tools can be projected from the endoscope simultaneously. For endoscopic treatment, ultrasonic endoscopes are desirably equipped with two channel and port sets for projecting treatment tools simultaneously.
However, a known ultrasonic endoscope is provided with an ultrasonic scanning system that is different from ordinary endoscopes. It has heretofore been difficult to provide the ultrasonic endoscope with a plurality of treatment tool projecting systems because such will further increase the size of the distal end of the insertion portion and thus causes great pain to the patient.
A first object, therefore, of the present invention is to provide the tip of an ultrasonic endoscope that is not unduly bulky at the distal end of the insertion portion and which is yet capable of high-level endoscopic treatment with two treatment tools being projected simultaneously.
With respect to reducing the size of the distal end of the insertion portion of an ultrasonic endoscope, it has been proposed by Japanese Patent Unexamined Publication No. Hei. 2-265533 to use an annular ultrasonic oscillator array for radial scanning, and to arrange optical members and a treatment tool projection port at a joint between adjacent ultrasonic oscillators.
Ultrasonic wave signals are not effectively transmitted through air. In order to perform ultrasonic scan within a body cavity, it is recommended that a balloon filled with deaerated or degasified water or the like be placed around the ultrasonic oscillator array and ultrasonic wave signals be transmitted and received through the balloon being pressed against the membrane in the body cavity.
However, if treatment tool projection port is provided between adjacent ultrasonic oscillators as in the arrangement disclosed by Japanese Patent Unexamined Publication No. Hei. 2-265533, the treatment tool, such as an injecting syringe, projecting from the port punctures the balloon and effective balloon-assisted ultrasonic examination cannot be performed
A second object, therefore, of the present invention is to provide the tip of an ultrasonic endoscope that uses a radial scanning, annular ultrasonic oscillator array, and which is capable of effective ultrasonic examination with a balloon attached so that the balloon is not potentially damaged with treatment tools.
The ultrasonic endoscope provided with a radial scanning, annular ultrasonic oscillator array suffers from another problem: Since the direction of ultrasonic scan lies in a plane normal to the longitudinal axis of the distal end of the insertion portion, the tip of a treatment tool must be guided and projected from the distal end of the insertion portion at an angle almost equal to 90 degrees.
This requirement causes the treatment tool to have the habit or tendency to bend and hinders smooth guiding of the tip of the endoscope to an aimed part. Further, since great resistance develops as the treatment tool is inserted into or removed out of the channel, the treatment tool may often buckle or otherwise break at the end which is closer to the operator.
A third object, therefore, of the present invention is to provide the tip of an ultrasonic endoscope that is equipped with a radial scanning, annular ultrasonic oscillator array and which permits treatment tools to project smoothly with limited occurrence of fatigue and breakage.
The present invention provides an arrangement for a tip of an ultrasonic endoscope, in which a treatment tool projection port is provided at a location longitudinally forward from a location where a radial scanning, annular ultrasonic oscillator array is provided. This arrangement makes it possible to prevent a treatment tool from damaging a balloon mounted around the annular ultrasonic oscillator array.
The present invention further provides an arrangement for a tip of an ultrasonic endoscope, in which two treatment tool projection ports are provided, one being located longitudinally forward from a location where a radial scanning, annular ultrasonic oscillator array is provided, and the other being located longitudinally rearward from the location where the annular ultrasonic oscillator is provided. This arrangement permits two treatment tools to project simultaneously from the tip of the endoscope without substantively increasing the size of the tip of the endoscope, thereby providing efficient endoscopic treatment.
The present invention further provides an arrangement for a tip of an ultrasonic endoscope, in which a radial scanning, annular ultrasonic oscillator array is arranged inclined, and a treatment tool projection port is provided at a location longitudinally rearward from a location where the annular ultrasonic oscillator array is provided. This arrangement make it possible to reduce an angle between a treatment tool projected from the treatment tool projection port and a longitudinal axis of the tip. Therefore, the treatment tool can project from the treatment tool projection port without great resistance, which would otherwise cause fatigue or damage of the treatment tool.
The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 10-363838, 10-363839 and 10-363840 (all filed on Dec. 22, 1998), all of which are expressly incorporated herein by reference in their entireties.